Connection to Global Positioning System (GPS)

From the
Hardware-HOWTO
I know there is Trimble Mobile GPS available for Linux.
You may also connect a GPS via a serial port. Most GPS receivers have
a data port and can connect to a PC with a special serial cable.

Differential GPS is a technique to apply a correction factor from a
known location to a GPS signal. This can substantially reduce the
uncertainity in the GPS location. Normally the correction signal is
acquired using a special radio receiver: dgpsip
allows you to receive a DGPS signal via TCP/IP, and send it to the GPS
connected to your serial port.

DGPS
is a project to put together a low cost hardware and software solution
for Differential GPS (in both real time mode using RTCM correction
format and in post processed mode).

gpsd
is a daemon that listens to a GPS or Loran receiver and translates
the positional data to simplified format that can be more easily
used by other programs, like chart plotters. The package comes with
a sample client that plots the location of the currently visible
GPS satellites (if available) and a speedometer. Added support for
the DeLame EarthMate as well as a new 'speedometer' mini client.

The
QtGPS
package contains a piece of software for
UNIX/Linux/X and a GPS receiver. It performs
logging and replaying of a journey, supporting a moving-map
display. QtGPS works with Lat/Long and British OSGB (Ornance
Survey) co-ordinate systems.

XASTIR
is a free APRS (Automatic Position Reporting System) program.
APRS(tm) was developed to track mobile GPS stations with
two-way radio to convey position reports, messaging, weather
and more. XASTIR plots this information on a map on your
screen where you can see the entire world or zoom down to
street level.

as-gps
contains a basic support library for accessing the
inexpensive ($20) Aisin-Seiki GPS Module previously
available at mavin.com. The package also includes several
simple console utilities for dumping satellite status,
location, and time and for synchronizing the system clock.

gmap
is a map viewer with emphasis on temporal data. It hopes
to evolve into a free and powerful Geographical
Information System.

gps3d
is a set of utilities that lets you manipulate your GPS
from your Linux box. One nice feature is the ability to
view GPS data (track, waypoints, fix, etc.) on an
OpenGL, 3D texture-mapped model of earth.